Carl binder



Patented Dec. 20, I898. c. BINDER.

ROOF.

(Application filed 091:. 10, 1898.)

(No Model.)

UNITED STATES PATENT OFFICE.

CARL BINDER, OF CHICAGO, ILLINOIS.

ROOF.

SPECIFICATION forming part of Letters Patent No. 616,180, dated December20, 1898.

Application filed OctoberlO, 1898. Serial No. 693,071. (No model.)

To all whom it may concern:

Be it known that I, CARL BINDER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in Roofs, of which the followingis a specification.

My invention relates particularly to an improvement in steel-roofconstruction; and my object is to decrease greatly the weight and 7 costof roofs.

In the accompanying drawings,which illustrate my improved construction,Figure 1 is a transverse vertical section of the roof,"taken asindicated at line 1 of Fig. 2; and Fig. 2, a view in side elevation ofthe same.

In the drawings, A A and B B represent the trusses (of any suitableform) of a simple construction of roof. These trusses are preferablyjoined together in pairs by suitable tie-rods t t and s s, as shown. Thetrusses are mounted upon the masonry or wall-plates of the side walls CC in any suitable manner or on columns.

Each truss is here shown as built up of a horizontal member or tie-beamq, rafters 10, and suitable posts and studs connecting the same.

Supported on the rafters are the longitudinally-extending purlins D D,&c., which may be channel-bars, as shown. These purlins are preferablysecured to the rafters by means of brackets or shoes n.

In ordinary construction the roof-trusses are located from ten to twentyfeet apart, and the common method heretofore has been to have thepurlins reach from truss to truss, the joint being located at therafter. In some cases the purlins have been made to span the distancebetween alternate trusses; but so far as I am aware it has been thecustom invariably to locate the joints immediately over the rafters.

My improvement consists in making the purlins up from sections of suchlength and so positioned that the joints are situated between trusses,preferably in the lnanner illustrated in Fig. 2. As there shown, eachpurlin is formed from members m of sufficient length to rest upon thejoined trusses and project at their ends beyond saidtrusses, and shortmembers m, joining the adjacent projecting ends of the members m. Themeeting ends of the members m and m may be joined together in anysuitable manner, as by means of plates m riveted thereto.

It will be observed that by means of the construction described thebending moment on each purlin is greatly reduced over what it is wherethe joints are over the rafters. In fact, the length of the members mand m may be so related to each other as to have the bending momentsupon the members m exactly coun teract each other. The result is thatthe elastic curve of the evenly-loaded purlins is changed greatly fromthat of the old construction and the fiexure of the purlins greatlyreduced, with a consequent lessening of the strain upon them. I am thusenabled to make the purlins of greatly-reduced cross-section, producinga saving of about one-third in material, amounting in one instance (thecase of a building now under contract by me) to many tons for this oneitem in the roof construction.

WVhile it is desirable to tie the trusses together in the manner shown,this is not necessary. Nor is it essential to the broad idea of myinvention that anyparticular section or member of apurlin extend overany given number of trusses, so long as the feature of forming thejoints between trusses is preserved. Preferably, however, each purlin ismade up of alternating long and short strips, the long strips extendingover two trusses, and in some instances over more than two.

The purlins serve to support the covering E, which may, rest directlyupon them or upon common rafters supported by them, the members 10 beingin the latter case regarded as the principal rafters.

What I claim as new, and desire to secure by Letters Patent, is-

1.- In a roof, the combination of suitablysupported, laterally-extendingtrusses, and

longitudinally-extending purlins supported thereby, said purlins beingformed of sections or members joined together, said members being ofsuch relative lengths and so positioned as to bring the joints betweentrusses, substantially as and for the purpose set forth.

2. In a roof, the combination of suitablysupported, laterally-extendingtrusses, and purlins supported thereby comprising members extending overtwo or more trusses and projecting at the ends beyond their supports,and members joining the same, the joints being located between trusses,substantially as and for the purpose set forth.

3. In a roof, the combination of suitablysupported, laterally'extendingtrusses, and purlins supported thereby comprising relatively longmembers extending over two or more trusses and projecting beyond said

